2010-30134. Airworthiness Directives; The Boeing Company Model 747-400 and -400D Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Model 747-400 and -400D series airplanes. This proposed AD would require a general visual inspection to determine the routing of the wire bundles in the number two and number three engine pylons near the leading edge, and related investigative and corrective actions, if necessary. For certain airplanes, this proposed AD would also require certain concurrent actions. This proposed AD results from a report of a fuel leak from the drain line of the number two engine pylon. We are proposing this AD to detect and correct chafing of the main fuel feed tube and the alternating current motor-driven hydraulic pump wire bundle, which could lead to arcing from the exposed wire to the fuel feed tube, and could result in a fire or explosion.

DATES:

We must receive comments on this proposed AD by January 18, 2011.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Tung Tran, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356, telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-1159; Directorate Identifier 2010-NM-006-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We received a report of a Model 747-400 airplane arriving at a gate with a fuel leak from the drain line of the number two engine pylon. An investigation revealed that the alternating current motor-driven pump wire bundle was incorrectly routed and touching the fuel feed tube, which caused chafing of the fuel feed tube and the resultant leak. If not detected and corrected, chafing of the main fuel feed tube and the alternating current motor-driven hydraulic pump wire bundle could lead to arcing from the exposed wire to the fuel feed tube, and could result in a fire or explosion.

Related AD

We issued AD 92-27-13, amendment 39-8448 (58 FR 5920, January 25, 1993), on December 17, 1992, for Model 747-400 series airplanes. We issued that AD to require repetitive inspections to detect damage, chafing, and improper clearance between the electrical power feeder cables and engine fuel supply tube, and corrective actions, if necessary; and modification of the electrical power feeder cable installation.

Relevant Service Information

We have reviewed Boeing Service Bulletin 747-29A2114, Revision 1, dated July 15, 2010. The service bulletin describes procedures for a general visual inspection to determine the routing of the wire bundles in the number two and number three engine pylons near the leading edge, and related investigative and corrective actions if necessary. Related investigative actions include a general visual inspection for damage between the wire bundle and the fuel feed tube. Corrective actions include repairing the wire bundle, repairing or replacing the fuel feed tube where the wire bundle goes across the tube, and changing the routing configuration for the wire bundle to above the support bracket.

Boeing Service Bulletin 747-29A2114, Revision 1, dated July 15, 2010, refers to Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991; Boeing Alert Service Bulletin 747-24A2168, Revision 2, dated September 24, 1992; or Boeing Service Bulletin 747-24A2168, Revision 3, dated July 29, 1993; for actions that must be done prior to or concurrently with the actions specified in Boeing Service Bulletin 747-29A2114, Revision 1, dated July 15, 2010. Boeing Service Bulletin 747-24A2168, Revision 3, dated July 29, 1993, specifies, for certain airplanes, procedures for installing the cable support brackets in the number two and number three strut, and related investigative and corrective actions, if necessary. The related investigative action is a detailed inspection of the clearance between the bracket and an adjacent pneumatic duct. The corrective action is adjusting the pneumatic duct, if necessary. AD 92-27-13 refers to Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991; and Revision 2, dated September 24, 1992; as appropriate sources of service information for doing certain actions required by that AD.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD would affect 15 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Table—Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per product	Number of U.S.-registered airplanes	Fleet cost
Inspection	1	$85	$0	$85	15	$1,275
Concurrent Inspection and Bracket Installation	6	85	0	510	15	7,650

The cost estimate figure discussed above is based on assumptions that no operator has yet accomplished any of the actions required by this proposed AD, and that no operator would accomplish those actions in the future if this AD were not adopted. However, we have been advised that the concurrent inspection and bracket installation have already been done on some affected airplanes. Therefore, the future economic cost impact of this rule on U.S. operators is expected to be less than the cost impact figure indicated above.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866,

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and

3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2010-1159; Directorate Identifier 2010-NM-006-AD.

Comments Due Date

(a) We must receive comments by January 18, 2011.

Affected ADs

(b) AD 92-27-13, Amendment 39-8448, affects this AD.

Applicability

(c) This AD applies to The Boeing Company Model 747-400 and -400D series airplanes, certificated in any category; as specified in Boeing Alert Service Bulletin 747-29A2114, Revision 1, dated July 15, 2010.

Subject

(d) Air Transport Association (ATA) of America Code 29: Hydraulic power.

Unsafe Condition

(e) This AD results from a report of a fuel leak from the drain line of the number two engine pylon. The Federal Aviation Administration is issuing this AD to detect and correct chafing of the main fuel feed tube and the alternating current motor-driven hydraulic pump wire bundle, which could lead to arcing from the exposed wire to the fuel feed tube, and could result in a fire or explosion.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspection

(g) Within 24 months after the effective date of this AD, do a general visual inspection to determine the routing of the wire bundles in the number two and number three engine pylons near the leading edge; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-29A2114, Revision 1, dated July 15, 2010. Do all applicable related investigative and corrective actions before further flight.

Concurrent Requirements

(h) For Model 747-400 series airplanes: Before or concurrently with accomplishing the requirements of paragraph (g) of this AD, install all applicable cable support brackets in the number two and number three engine pylon areas, and do all applicable related investigative and corrective actions, in accordance with Phase II of Boeing Service Bulletin 747-24A2168, Revision 3, dated July 29, 1993. Do all applicable related investigative and corrective actions before further flight. Doing the actions required by paragraph (c) of AD 92-27-13, Amendment 39-8488, is an acceptable method of compliance with the installation required by this paragraph.

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Credit for Actions Accomplished in Accordance With Previous Service Information

(i) Actions accomplished before the effective date of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-29A2114, dated October 1, 2009, are considered acceptable for compliance with the corresponding actions specified in paragraph (g) of this AD.

(j) Actions accomplished before the effective date of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-24A2168, Revision 1, dated December 5, 1991; or Revision 2, dated September 24, 1992; are considered acceptable for compliance with the corresponding actions specified in paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Tung Tran, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356, telephone [phone]; fax [phone]. Information may be e-mailed to: [e-mail].

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on November 15, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.